Proteins from anaerobic fungi and uses thereof

ABSTRACT

Provided herein are novel proteins and protein domains from newly discovered anaerobic fungal species. The anaerobic fungal species have unique enzymatic capabilities, including the ability to digest diverse lignocellulosic biomass feedstocks and to synthesize secondary metabolites. The scope of the invention encompasses novel engineered proteins comprising glycoside hydrolase enzymes, dockerin domains, carbohydrate binding domains, and polyketide synthase enzymes. The invention further encompasses artificial cellulosomes comprising novel proteins and domains of the invention. The scope of the invention further includes novel nucleic acid sequences coding for the engineered proteins of the invention, and methods of using such engineered organisms to degrade lignocellulosic biomass and to create polyketides.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to International Patent ApplicationNumber PCT/US2016/065579, entitled “Novel Proteins from Anaerobic Fungiand Uses Thereof” filed on Dec. 8, 2016, which claims priority to U.S.Provisional Patent Application No. 62/265,397 entitled “Novel PolyketideSynthase Domains from Fungal Organisms,” filed Dec. 9, 2015 and U.S.Provisional Application Ser. No. 62/296,064 entitled “Production ofBiofuels from Novel Fungal Strains and Enzymes Derived Therefrom,” filedFeb. 16, 2016, the contents which are hereby incorporated by reference.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

This invention was made with government support under grant numberW911NF-09-D-0001 awarded by the United States Army. The government hascertain rights in the invention.

REFERENCE TO SEQUENCE LISTING, A TABLE, OR A COMPUTER PROGRAM LISTINGCOMPACT DISK APPENDIX

The instant application contains a Sequence Listing which has been filedelectronically in ASCII format and is hereby incorporated by referencein its entirety. Said ASCII copy, created on Dec. 6, 2016, is namedUCSB007PCT_SL.txt and is 21,694,502 bytes in size.

BACKGROUND OF THE INVENTION

Microbial communities have evolved immense enzymatic capabilities. Inparticular, anaerobic fungi perform metabolic feats which potentiallycould be adapted for great benefit. For example, the efficientconversion of biomass into fuels could provide humankind with aninexpensive, unlimited, and environmentally sustainable source ofenergy. However, current biomass conversion technologies are noteconomically scalable due to the recalcitrance of woody biomass. Whilehumans have struggled to effectively capture energy from biomass,anaerobic fungi efficiently convert such material into many billions ofjoules of energy each day, in the digestive tracts of herbivores. Theseorganisms have evolved efficient enzymatic machinery to break downcellulosic material in lignin rich plant material.

In addition to efficiently breaking down biomolecules, anaerobic fungiare able to synthesize complex natural products which are difficult orimpossible to make using synthetic chemistry. Fungi have rich enzymaticabilities which create a diversity of biologically active molecules.Roughly 40% of drugs in use today were derived from fungi, for example,including antibiotics such as penicillin, chemotherapeutics such asvincristine or vinblastine, and cholesterol-lowering drugs such asstatins. The prevalence of useful biomolecules produced by fungi isenabled by their unique enzymatic capabilities.

While the potential of fungi to improve bioproduction technologies ishuge, large numbers of fungal species cannot contribute because they arenot amenable to culture, isolation, and study. Anaerobic fungi inparticular are very difficult to culture compared to model organismssuch as aerobic bacteria or yeast. The anaerobic fungi have thereforebeen severely underrepresented in bioprospecting efforts due to thebottlenecks associated with their study.

Advantageously, the inventors of the present disclosure have developedmethodologies for the culture of anaerobic fungi. This development hasenable the isolation and characterization of organisms which were neverpreviously studied. From this work, novel species of gut fungi have beenisolated and their transcriptomes have been sequenced, revealing amultitude of new genes and proteins that can be used in energyproduction, in the synthesis of novel compounds, and in otherapplications.

SUMMARY OF THE INVENTION

The inventors of the present disclosure have identified four novelspecies of anaerobic fungi and have identified numerous useful proteindomains and nucleic acid sequences coding therefor. These novelsequences provide the art with new enzymatic tools. In one aspect, theinvention is directed to methods and compositions of matter utilized inthe production of biofuels from lignocellulosic biomass utilizing thenovel domains of the invention. In one aspect, the scope of theinvention encompasses novel catalytic domains applied in the digestionof lignocellulosic biomass. In another aspect, the scope of theinvention encompasses structural components which are incorporated intoenzyme complexes, such as cellulosomes. Disclosed herein are novelengineered scaffoldins, glycoside hydrolase enzymes, dockerins,cohesins, and domains therefrom, as well as other catalytic proteins andprotein domains involved in the breakdown of plant material. In anotheraspect, the scope of the invention encompasses methods of producingbiofuels utilizing the novel organisms described herein in bioreactorsor like processes.

In yet another aspect, the scope of the invention encompasses methodsand compositions of matter which are utilized in the production ofsecondary compounds, such as polyketides. In one aspect, thecompositions of the invention encompass engineered polyketide synthasecomplexes comprising one or more novel domains of the invention. Inanother aspect, the scope of the invention encompasses methods of usingthe domains of the invention in the production of secondary compounds.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a conceptual diagram of a cellulosome. The cellulosome complexcomprises a scaffoldin (104), comprising a plurality of cohesins (105).Enzymatic moieties comprising catalytic domains (106) are attached tothe scaffold by the docking of dockerins (107) to complementary cohesionmolecules in dockerin-cohesin complexes (111). The docked proteinsfurther include carbohydrate binding entities (108). The cellulosome isanchored in the cell membrane (103) of a host cell (101) by an anchoringmoiety such as a transmembrane helix (102). The cellulosome can digest acomplex polymer (109) such as cellulose into monomers (110).

DETAILED DESCRIPTION OF THE INVENTION

Four novel anaerobic gut fungi were isolated and cultured. The organismsinclude Piromyces finnis isolated from horse feces, Neocallimastixcaliforniae, isolated from goat feces, Anaeromyces robustus, isolatedfrom sheep feces, and Neocallimastix sp S4, isolated from sheep feces.

Utilizing novel culture methods, the organisms were isolated and purecultures were attained, enabling the performance of sequencing efforts.Next-generation sequencing techniques were then utilized identifysequences expressed by the fungal cells. DNA analysis tools were thenused to identify domains present in the expressed proteins. By theirhomology to known sequences, numerous types of useful domains wereidentified, including catalytic domains and structural domains.

The several domains identified are provided in the sequence listingsubmitted herewith. Table 1 lists domain names and a description foreach domain name which identifies a gene or gene family associated withthe sequence, as assigned by bioinformatic tools.

Each domain is represented as a novel polypeptide sequence having adomain description based on its similarity to known proteins from otherorganisms. Each domain is also provided as a nucleic acid sequencecoding for the disclosed polypeptides. The listed protein sequences areprovided in standard one-letter amino acid code, as known in the art.The listed nucleic acid sequences comprise fungal cDNA sequences. In thenucleic acids sequence listings, A is adenine; C is cytosine; G isguanine; T is thymine; and N is any of the four bases. The codonpreferences of the anaerobic fungi are generally in line with those ofmodel organisms, although fungal sequences tend to have a higher A-Tcontent.

It will be noted that in some cases, multiple variants of a domain arelisted, having been derived from the same transcript sequence. This isdue to the use of multiple genetic identification tools, which in somecases use diverging models to recognize, define, and annotate proteindomains. These models recognize a number of unique features, such as theN- or C-termini of catalytic domains, key catalytic residues, etc, eachwith their own start and stop sites, resulting in overlapping domainannotations for some transcripts.

The present disclosure provides the art with a large number of novelprotein domains and corresponding nucleic acid sequences that may beapplied in various contexts. Domains which are applicable to the variouscompositions and methods described herein can be readily selected fromthe sequence listing submitted based on the domain labels anddescriptions provided in Table 1.

TABLE 1 Domain labels, descriptions, and SEQ ID NO.'s. Protein NucleicSeq ID Acid Seq. Domain Label Domain Description No.'s ID No.'s(Trans)glycosidases Glycosidase  1-155 13663-13818 1-1-Phosphatidylinositol 156-157 13819-13820 PHOSPHATIDYLINOSITOLphosophodiesterase PHOSPHODIESTERASE- RELATED PROTEIN4-PPantetheinyl_Trfase_SF 4′-phosphopantetheinyl 158-165 13821-13827transferase 4′-phosphopantetheinyl 4′-phosphopantetheinyl 166-17313828-13835 transferase transferase 6-blade_b-propeller_TolB- six-bladedbeta-propeller domain 174 13836 like found in TolB protein6hp_glycosidase Glycosidase-six hairpin type 175-322 13837-139849-O-ACETYL-N- 9-O-acetyl-N-acetylneuraminic 323-333 13885-13995ACETYLNEURAMINIC acid deacetylase ACID DEACETYLASE- RELATED AAC-RICHMRNA CLONE AAC-RICH MRNA CLONE 334 13996 AAC4 PROTEIN-RELATED AAC4PROTEIN-RELATED AB_hydrolase Alpha-beta hydrolase fold 335-45013997-14112 domain found in hydrolytic enzymes Abhydrolase_5 Alpha-betahydrolase fold 451-464 14113-14126 domain 5 found in hydrolytic enzymesAc_transferase_dom Acyl Transferase Domain 465-578 14127-14240 ACCESSORYGLAND Accessory Gland Protein domain 579-583 14241-14245 PROTEIN ACP76A-with similarity to that found in RELATED flies Acetyl-CoAsynthetase-like Acetyl CoA Synthetase 584-603 14246-14265 ACIDPHOSPHATASE Acid phosphatase 604-623 14266-14285 RELATED ACP_DOMAIN AcylCarrier Protein 624-668 14286-14330 ACP-like Acyl Carrier Protein669-714 14331-14376 ACPS Acyl Carrier Protein Synthase, a 715-72214377-14384 phosphopantetheinyl transferase Acyl_carrier_prot-like AcylCarrier Protein 723-767 14385-14429 Acyl_transf_1 Acyl Transferase768-798 14430-14460 ACYL-COA Acyl CoA Thioesterase I 799 14461THIOESTERASE I ADH_N Catalytic domain of alcohol 800-807 14462-14469dehydrogenase adh_short Domain from short chain 808-823 14470-14485dehydrogenase family adh_short_C2 Domain from short chain 824-83214486-14494 dehydrogenase C2 family ADH_ZINC Domain from alcohol 833-83514495-14497 dehydrogenase, zinc type ADH_zinc_N Domain from alcohol836-851 14498-14513 dehydrogenase, zinc type ALCOHOL Domain from alcohol852-862 14514-14524 DEHYDROGENASE dehydrogenase RELATED Aldolase_TIMbeta/alpha barrel domain found 863-870 14525-14532 in aldolasesALPHA-L-FUCOSIDASE 2 Alpha-L-fucosidase 871-874 14533-14536alpha/beta-Hydrolases Alpha-beta hydrolase fold 875-972 14537-14634domain found in hydrolytic enzymes Aminotran_1_2 Class I/Class II973-982 14635-14644 Aminotransferase AMP_BINDING AMP binding domain983-999 14645-14661 AMP-binding_C C terminal domain of AMP 1000-100114662-14663 binding enzyme Arabinanase/levansucrase/invertase Member of1002-1058 14664-14720 Arabinanase/levansucrase/invertase superfamilyARF/SAR SUPERFAMILY Member of small GTPASE 1059-1060 14721-14722PROTEIN-RELATED superfamily AT18611P-RELATED Carbohydrate binding domain1061-1062 14723-14724 B_KETOACYL_SYNTHASE Beta-ketoacyl-ACP synthase1063-1094 14725-14756 Barwin-like endoglucanases Endoglocanase 1095-120414757-14866 Beta_cellobiohydrolase 1,4-beta cellobiohydrolase 1205-128614867-14948 Beta-D-glucan exohydrolase, Beta-D-glucan exohydrolase, C-1287-1297 14949-14959 C-terminal domain terminal domainBETA-GALACTOSIDASE Glycoside hydrolase Beta- 1298-1303 14960-14965Galasctosidase beta- beta- 1304-1309 14966-14971Galactosidase/glucuronidase Galactosidase/glucuronidase domain domainBETA/GAMMA Beta-Gamma Crystallin 1310-1316 14972-14978 CRYSTALLINStructural Protein Bgal_small_N Beta-galactosidase small chain 1317-132214979-14984 BNR BNR repeat sequence 1323-1324 14985-14986 Carb_bindCarbohydrate Binding Domain 1325-1327 14987-14989 Carbohydrate-bindingdomain Carbohydrate Binding Domain 1328-1333 14990-14995CarboxyPept_regulatory_dom Regulatory domain of 1334-1337 14996-14999carboxypeptidase CBD_carb-bd_dom Carbohydrate Binding Domain 1338-134415000-15006 CBD_IV Cellulose binding domain, Type 1345-1370 15007-15032IV CBM_1 Fungal cellulose binding domain 1371-1419 15033-15081 CBM_10Dockerin and Carbohydrate 1420-3705 15082-17367 Binding Domain, Type 10CBM_2 Carbohydrate Binding Domain, 3706-3709 17368-17371 Type 2 CBM_4_9Carbohydrate Binding Domain 3710-3714 17372-17376 CBM_6 CarbohydrateBinding Domain, 3715-3736 17377-17398 family 6 CBM-like CarbohydrateBinding Domain 3737-3740 17399-17402 CBM1_1 Carbohydrate Binding Domain3740-3758 17403-17420 CBM1_2 Carbohydrate Binding Domain 3759-384117421-17503 CBM6 Carbohydrate Binding Domain, 3842-3850 17504-17512family 6 Cellulase Cellulase 3851-3962 17513-17624 CELLULASE (GLYCOSYLCellulase-glycosyl hydrolase 3963-3972 17625-17634 HYDROLASE FAMILY 5)family 5 PROTEIN-RELATED Cellulose docking domain, Carbohydrate BindingDomain 3973-6217 17635-19879 dockering Cellulose-binding domainCarbohydrate Binding Domain 6218-6254 19880-19916 CHB_HEX_CChitinase-Chitobiase, C 6255-6262 19917-19924 terminal domainCHIT_BIND_I_1 Chitin Binding Site, Type 1, may 6263-6265 19923-19927bind N-acetylglucosamine CHIT_BIND_I_2 Chitin Binding Site, Type 1, may6266-6270 19928-19932 bind N-acetylglucosamine CHITIN DEACETYLASE 1-allantoinase/chitin deacetylase 1 6271 19933 RELATED Chitin_bind_1Chitin Binding Site, Type 1, may 6272-6275 19934-19937 bindN-acetylglucosamine Chitin-bd_1 Chitin Binding Site, Type 1, may6276-6282 19938-19944 bind N-acetylglucosamine CHITINASE Chitinase6283-6291 19945-19953 Chitinase insertion domain Chitinase insertiondomain 6292-6300 19954-19962 CHITINASE_18 Chitinase, family 18 6301-630319963-19965 Chitinase_insertion Chitinase insertion domain 6304-631219966-19974 Chitobiase/Hex_dom_2-like domain 2 of bacterial chitobiases6313-6314 19975-19976 and beta-hexosaminidases ChtBD1 Chitin BindingSite, Type 1, may 6315-6318 19977-19980 bind N-acetylglucosamineCINNAMYL ALCOHOL cinnamyl-alcohol dehydrogenase 6319-6322 19981-19984DEHYDROGENASE 2- RELATED ClpP/crotonase Crotonase like domain 6323-633319985-19995 ClpP/crotonase-like_dom Crotonase like domain 6334-634419996-20006 CoA-dependent CoA-dependent acyltransferases 6345-634920007-20011 acyltransferases ConA-like_subgrp Concanavalin A-like6350-6375 20012-20037 lectins/glucanases Concanavalin A-likeConcanavalin A-like 6376-6433 20038-20095 lectins/glucanaseslectins/glucanases Condensation Condensation domain 6434-643620096-20098 CotH spore coat protein, involved in 6437-6584 20099-20246plant cell wall binding Cystine-knot_cytokine Cystine-knot_cytokine 658520247 CYTH-like phosphatases Phosphatase-acts on 6586-6587 20248-20249triphosphorylated substrates CYTH-like_domain Phosphatase-acts on6588-6589 20250-20251 triphosphorylated substrates Dockerin_dom Dockerindomain 6590-7679 20252-21341 Dockerin_dom_fun Dockerin domain 7680-891021342-22572 DPBB_1 Lytic transglycolase 8911-8919 22573-22581 DUF1729Domain of unknown function- 8920-8930 22582-22592 Found in acyltransferase domains DUF303 Domain of unknown function 8931-894622593-22608 DUF303, acetylesterase DUF4353 Domain of unknown function8947-8949 22609-22611 ECH Enoyl-CoA hydratase 8950-8959 22612-22621EGGSHELL eggshell 8960-8963 22622-22625 Endo-1-4-beta-Endo-1-4-beta-glucanase, 8964 22626 glucanase_dom2 domain 2ENDO-1,4-BETA- Endo-1-4-beta-glucanase 8965-8998 22627-22660 GLUCANASEENDOGLUCANASE Endoglucanse 8999-9022 22661-22684 Endoglucanase_F_dom3Endoglucanse F, domain 3 9023-9055 22685-22717 ENTEROBACTIN EntorbactinSynthase 9056 22718 SYNTHASE COMPONENT F Component F Esterase Esterase9057-9080 22719-22742 Expansin_CBD C-terminal carbohydrate binding9081-9106 22743-22768 domain of expansin EXPANSIN_EG45 N terminal domainof expansin 9107-9127 22769-22789 EXTRACELLULAR Extracellular matrixglycoprotein 9128-9129 22790-22791 MATRIX GLYCOPROTEIN related domainRELATED FabD/lysophospholipase-like FabD/lysophospholipase-like9130-9240 22792-22902 domain-found in hydrolases FAMILY NOT NAMED Notassociated with known 9240-9338 22903-23600 sequences FASYNTHASE FattyAcid Synthase 9339-9468 23601-23130 FATTY ACID SYNTHASE Fatty AcidSynthase-subunit 9469-9479 23131-23141 SUBUNIT BETA beta fCBD Cellulosebinding domain 9480-9605 23142-23267 fn3_3 domain II of 9606-960923268-23271 rhamnogalacturonan lyase Fn3_assoc domain II of 9610 23272rhamnogalacturonan lyase Fn3-like domain II of 9611-9619 23273-23281rhamnogalacturonan lyase Galactose mutarotase-like Galactosemutarotase-like 9620-9626 23282-23288 domain-binds carbohydratesGalactose-bd-like Galactose binding domain-like 9627-9668 23289-23330fold Galactose-binding domain- Galactose binding domain-like 9669-972723331-23389 like fold GDHRDH short-chain 9728-9748 23390-23410dehydrogenases/reductase family GH_fam_N_dom domain is found towards theN 9749-9753 23411-23415 terminus of some glycosyl hydrolase familymembers, including alpha-L-fucosidases GH04125P-RELATED Serine proteaseinhibitor related 9754 23416 GH97_C Glycosyl-hydrolase 97, C- 9755 23417terminal oligomerisation domain GH97_N Glycosyl-hydrolase 97, N- 975623418 terminal domain GLHYDRLASE10 Glycoside hydrolase family 109757-9889 23419-23551 domain GLHYDRLASE11 Glycoside hydrolase family 119890-9998 23552-23660 GLHYDRLASE16 Glycoside hydrolase family 16 9999-10013 23661-23675 GLHYDRLASE2 Glycoside hydrolase family 210014-10028 23676-23690 GLHYDRLASE26 Glycoside hydrolase family 2610029-10054 23691-23716 GLHYDRLASE3 Glycoside hydrolase, family 3,10055-10094 23717-23756 N-terminal GLHYDRLASE48 Glycoside hydrolasefamily 48 10095-10308 23757-23970 GLHYDRLASE6 Glycoside hydrolase family6 10309-10791 23971-24453 GLHYDRLASE8 Glycoside hydrolase family 810792-10818 24454-24480 GLUCOSE-METHANOL- Glucose-methanol-choline10819-10820 24481-24482 CHOLINE (GMC) oxidoreductase OXIDOREDUCTASEGLUCOSYLCERAMIDASE Glucosylceramidase 10821-10823 24483-24485 Glyco_10Glycoside hydrolase family 10 10824-10858 24486-24520 Glyco_18 Glycosidehydrolase family 18 10859-10865 24520-24572 Glyco_hyd_65N_2 N-terminusof the glycosyl 10866-10870 24573-24532 hydrolase 65 family catalyticdomain Glyco_hydr_30_2 Glycoside hydrolase family 30 10871-1087324533-24535 Glyco_hydro_10 Glycoside hydrolase family 10 10874-1091324536-24575 Glyco_hydro_11 Glycoside hydrolase family 11 10914-1094924576-24611 Glyco_hydro_11/12 Glycoside hydrolase family 10950-1098624612-24684 11/12 Glyco_hydro_114 Glycosyl-hydrolase family, 10987-1098924685-24651 number 114potential endo-alpha- 1,4-polygalactosaminidaseGlyco_hydro_13_b Glycoside hydrolase family 13 10990-10991 24652-24653Glyco_hydro_16 Glycoside hydrolase family 16 10992-11001 24654-24663Glyco_hydro_18 Glycoside hydrolase family 18 11002-11010 24664-24672Glyco_hydro_2 Glycoside hydrolase family 2 11011-11013 24673-24675Glyco_hydro_2_C Glycoside hydrolase family 2 11014-11016 24676-24678Glyco_hydro_2_N Glycoside hydrolase family 2-N 11017-11019 24679-24681terminal domain Glyco_hydro_2/20_Ig-like Glycoside hydrolase, family11020-11025 24682-24687 2/20, immunoglobulin-like beta- sandwich domainGlyco_hydro_26 Glycoside hydrolase family 26 11026-11032 24688-24694Glyco_hydro_3 Glycoside hydrolase family 3 11033-11041 24695-24703Glyco_hydro_3_C Glycoside hydrolase family 3-C 11042-11059 24704-24721terminal domain Glyco_hydro_3_N Glycoside hydrolase family 3-N11060-11068 24722-24730 terminal domain Glyco_hydro_39 Glycosidehydrolase family 39 11069-11081 24731-24743 Glyco_hydro_43 Glycosidehydrolase family 43 11082-11129 24744-24791 Glyco_hydro_45 Glycosidehydrolase family 45 11130-11153 24792-24815 Glyco_hydro_48 Glycosidehydrolase family 48 11154-11186 24816-24848 Glyco_hydro_53 Glycosidehydrolase family 53 11187-11189 24849-24851 Glyco_hydro_6 Glycosidehydrolase family 6 11190-11270 24852-24932 Glyco_hydro_8 Glycosidehydrolase family 8 11271-11276 24933-24938 Glyco_hydro_88 Glycosidehydrolase family 88 11277-11278 24939-24940 Glyco_hydro_9 Glycosidehydrolase family 9 11279-11312 24941-24974 Glyco_hydro_97 Glycosidehydrolase family 97 11313 24975 Glyco_hydro_beta-prop five-bladedbeta-propellor 11314-11361 24976-25023 domain found in some glycosylhydrolases Glyco_hydro_catalytic_dom catalytic TIM beta/alpha barrel11362-11510 25024-25172 common to many different families of glycosylhydrolases Glyco_hydro-type_carb- Carbohydrate binding domain11511-11517 25173-25179 bd_sub from glycoside hydrolases GlycosideGlycoside hydrolase/deacetylase 11518-11521 25180-25183hydrolase/deacetylase family GLYCOSYL HYDROLASE Glycoside hydrolasefamily 43 11522-11560 25184-25222 43 FAMILY MEMBER Glycosyl hydrolasedomain catalytic TIM beta/alpha barrel 11561-11562 25223-25224 common tomany different families of glycosyl hydrolases GLYCOSYL HYDROLASE-related to known glycosyl 11563-11564 25225-25226 RELATED hydrolasedomains Glycosyl hydrolases family 6, Glycosyl hydrolases family 6,11565-11648 25227-25310 cellulases cellulases GLYCOSYL Glycosyltransferase related 11649-11669 25311-25331 TRANSFERASE-RELATED domainGLYCOSYL_HYDROL_F10 Glycoside hydrolase family 10 11670-1168825332-25350 GLYCOSYL_HYDROL_F11_1 Glycoside hydrolase family 1111689-11719 25351-25381 GLYCOSYL_HYDROL_F11_2 Glycoside hydrolase family11 11720-11721 25382-25383 GLYCOSYL_HYDROL_F3 Glycoside hydrolase family3 11722 25384 GLYCOSYL_HYDROL_F45 Glycoside hydrolase family 4511723-11742 25385-25404 GLYCOSYL_HYDROL_F5 Glycoside hydrolase family 511743-11765 25405-25427 GLYCOSYL_HYDROL_F6_2 Glycoside hydrolase family6 11766-11816 25428-25478 GLYCOSYL_HYDROL_F9_2 Glycoside hydrolasefamily 9- 11817-11844 25479-25506 signature found in endglucanases andother glycoside hydrolases GroES-like Similarity to GroES (chaperonin11845-11882 25507-25544 10), an oligomeric molecular chaperoneHMG_CoA_synt_C Hydroxymethylglutaryl- 11883-11888 245545-25550 coenzymeA synthase C-terminal domain HMG_CoA_synt_N Hydroxymethylglutaryl-11889-11891 25551-25553 coenzyme A synthase N- terminal domainHotDog_dom domain found in thioesterases 11892-11921 25554-25583 andthiol ester dehydratase- isomerases HxxPF_rpt HxxPF-repeat domain. 1192225584 This family is found in non- ribosomal peptide synthetaseproteins. ICP-like ICP-like domain 11923 25585 Inhibitor_I42 Proteaseinhibitor 11924 25586 Inosine monophosphate Inosine monophosphate11925-11933 25587-25595 dehydrogenase (IMPDH) dehydrogenase Integrinalpha N-terminal Integrin alpha N-terminal 11934-11937 25596-25599domain domain KAZAL_1 serine proteinase inhibitor 11938 25600ketoacyl-synt Beta-ketoacyl synthase 11939-11983 25601-25645Ketoacyl-synt_C Beta-ketoacyl synthase, C- 11984-12027 25646-25689terminal domain KR Ketoreductase 12028-12043 25690-25705 L domain-likeLeucine rich repeat domain 12044-12047 25706-25709 LamGL LamG-likejellyroll fold 12048-12050 25710-25712 Laminin_G_3 This domain belongsto the 12051-12053 25713-25715 Concanavalin A-like lectin/glucanasessuperfamily LEUCINE-RICH REPEAT Leucine-Rich Repeat Receptor-12054-12057 25716-25719 RECEPTOR-LIKE Like Kinase1 PROTEIN KINASELipase_GDSL Domain from GDSL esterases 12058-12067 25720-25729 andlipases Lipase_GDSL_2 Domain from family of 12068-12070 25730-25732presumed lipases and related enzymes LRR Leucine rich repeat 12071-1208225733-25744 LRR_1 Leucine rich repeat 12083-12090 25745-25752 LRR_4Leucine rich repeat 12091-12093 25753-25755 LRR_6 Leucine rich repeat12094 25756 LRR_8 Leucine rich repeat 12095-12098 25757-25760 LRR_SD22Leucine rich repeat 12099-12101 25761-25763 LRR_TYP Leucine richrepeat-typical 12102-12116 25764-25778 subtype LYSOPHOSPHOLIPASE-Lysophospholipase related 12117 25779 RELATED domain MALONYL COA-ACYLMalonyl-CoA: acyl carrier 12118-12128 25780-25790 CARRIER PROTEINprotein transacylase TRANSACYLASE MaoC_dehydrat_N N-terminal domain ofMaoC 12129-12137 25791-25799 dehydratase MaoC_dehydratas C-terminaldoamin of MaoC 12138-12152 257800-25814  dehydratase Metallo-dependentMetallo-dependent phosphatases 12153-12202 25815-25864 phosphatasesMetallo-depent_PP-like Metallo-dependent phosphatases 12203-1224525865-25907 Metallophos Metallo-dependent phosphatases 12246-1228125908-25943 Mucin Mucins, high molecular weight 12282-12283 25944-25945glycoconjugates NAD(P)-bd_dom NADP binding domain 12284-1233425946-25996 NAD(P)-binding Rossmann- NAD(P)-binding Rossmann-fold12335-12384 25997-26046 fold domains domains NODB catalytic domain foundin 12385 26047 members of carbohydrate esterase family 4 Oligoxyloglucanreducing Oligoxyloglucan reducing end- 12386-12397 26048-26059end-specific specific cellobiohydrolase cellobiohydrolase Pectinlyase-like Pectin-lyase like domain 12398-12408 26060-26070Pectin_lyas_fold Pectin lyase fold domain 12409-12417 26071-26079Peptidase_S8 Peptidase_S8 12418-12421 26080-26083 Peptidase_S8/S53_domdomain found in serine 12422-12427 26084-26089 peptidases PERIPLASMICBETA- Periplasmic Beta-glucosidase 12428-12437 26090-26099GLUCOSIDASE-RELATED related domain PERIPLASMIC BROAD- Periplasmic broadspecificity 12438-12441 26100-26103 SPECIFICITY esterase/lipase/proteaseESTERASE/LIPASE/PROTEASE PEROXISOMAL Peroxisomal multifunctional12442-12445  2614-26107 MULTIFUNCTIONAL enzyme type 2 ENZYME TYPE 2 PHLpollen allergen PHL pollen allergen 12446-12462 26108-26124PHOSPHOPANTETHEINE Prosthetic group of acyl carrier 12463-1247326125-26135 protein PI-PLC-X PI-PLC X domain 12474 26136-26137 12475PIPLC_X_DOMAIN PI-PLC X domain 12476-12478 26138-26140 PKS_AT AcylTransferase domain 12479-12509 26141-26171 PKS_ER Enoyl Reductase12510-12525 26172-26178 PKS_KR Ketoreductase 12526-12545 26179-26198PKS_KS Ketosynthase 12546-12579 26199-26241 PKS_PPphosphopantetheine-binding 12580-12607 26242-26269 domain Plantlectins/antimicrobial Plant lectins/antimicrobial 12608-1261226270-26274 peptides peptides PLC-like phosphodiesterases PLC-likephosphodiesterases 12613-12618 26275-26280 PLC-like_Pdiesterase_TIM-domain consisting of a TIM 12619-12622 26281-26284 brlbeta/alpha-barrel, found in several phospholipase C likephosphodiesterases PLCXc Phosphatidylinositol-specific 12623-1262426285-26286 phospholipase C, X domain PLP-dependent transferasesPLP-dependent transferases 12625-12634 26287-26296 POLYKETIDE SYNTHASE-Related to sequences found in 12635-12679 26297-26314 RELATED PKSdomains Polysac_deacetylase Polysaccharide deacetylase 12680-1268326314-26345 Polysacc_deac_1 domain found in polysaccharide 12684-1268726346-26349 deacetylase PP-binding phosphopantetheine-binding12688-12727 26350-26389 domain Probable ACP-binding Probable ACP-bindingdomain 12728-12740 26390-26402 domain of malonyl-CoA ACP of malonyl-CoAACP transacylase transacylase PROKAR_LIPOPROTEIN Prokaryotic lipoproteindomain 12741-12761 26403-26423 PROPROTEIN Proprotein convertase12762-12764 26424-26426 CONVERTASE subtilisin/kexin type 9SUBTILISIN/KEXIN PROSTAGLANDIN Prostaglandin reductase 1 12765-1276726427-26429 REDUCTASE 1 domain PROTEIN C41A3.1 Protein C41A3.112768-12770 26430-26432 PS-DH Polyketide synthase, dehydratase12771-12785 26433-26447 domain PT Polyketide product template12786-12787 26448-26449 domain PURPLE ACID purple acid phosphatase 2312788-12797 26450-26459 PHOSPHATASE 23 Purple acid phosphatase, N-Purple acid phosphatase, N- 12898-12829 26460-26491 terminal domainterminal domain Purple_acid_Pase_N Purple acid phosphatase, N-12830-12861 26492-26523 terminal domain PyrdxlP- Pyridoxalphosphate-dependent 12862-12871 26524-26533 dep_Trfase_major_sub1transferase, major region, subdomain 1 PyrdxlP- Pyridoxalphosphate-dependent 12872-12879 26534-26541 dep_Trfase_major_sub2transferase, major region, subdomain 2 Rhamnogal_lyaseRhamnogalacturonate lyase 12880-12883 26542-26545 RhgB_NRhamnogalacturonase B, N- 12884-12885 26546-26547 terminal domain RICINRicin 12886-12950 26548-26612 Ricin B-like lectins Ricin B-like lectins12951-13037 26613-26699 RICIN_B_LECTIN Ricin B-like lectins 13038-1310826699-26770 RicinB_lectin_2 Ricin B-like lectins 13109-13186 26771-26848SCP-like Spore coat protein like domain 13187-13189 26849-26851 SCP2Spore coat protein 2 13190-13192 26852-26854 SCP2_sterol-bd_dom SCP2sterol-binding domain 13193-13195 26855-26857 SDRFAMILY Short-chain13196-13207 26858-26869 dehydrogenase/reductase SERINE PROTEASE Serineprotease inhibitor 13208-13215 26870-26877 INHIBITOR, SERPINSERINE/THREONINE Serine/threonine protein kinase 13216 26878-26878PROTEIN KINASE SERPIN Serine protease inhibitor 13217-13242 26879-26904Serpins Serine protease inhibitor 13243-13253 26905-26915 SGNH hydrolaseSGNH hydrolase domain 13252-13294 26916-26956 SGNH_hydro- SGNHhydro-typeesterase 13295-13307 26957-26969 type_esterase_dom domain Six-hairpinglycosidases six-hairpin glycoside domain 13308-13389 26970-27051Starch-binding domain-like Starch-binding domain-like 13392-1339327052-27055 SUBTILASE_ASP Serine proteases, subtilase 13394-1339527056-27057 family, aspartic acid active site SUBTILASE_HIS Serineproteases, subtilase 13396-13397 27058-27059 family, histidine activesite. SUBTILASE_SER Serine proteases, subtilase 13398-13399 27060-27061family, serine active site. SUBTILISIN Protease domain 13400-1340727062-27069 Subtilisin-like Subtilisin-like protease domain 13408-1341627070-27078 Thioesterase Thioesterase 13417-13419 27079-27081Thioesterase/thiol ester Thioesterase/thiol ester 13420-1344927082-27111 dehydrase-isomerase dehydrase-isomerase Thiolase-likeThiolase-like domain 13450-13544 27112-27206 Thiolase-like_subgrThiolase-like_subgr 13545-13637 27207-27299 Thioredoxin-likeThioredoxin-like 13638 27300 Thioredoxin-like_fold Thioredoxin-like folddomain 13639 27301 TIGR00556 phosphopantethiene--protein 13640-1364727302-27309 transferase domain TIGR01733 amino acid adenylation domain13648 27310 TIGR01833 hydroxymethylglutaryl-CoA 13649-13650 27311-27312synthase TRANS-2-ENOYL-COA Enoyl-CoA reductase 13651-13654 27313-27316REDUCTASE, MITOCHONDRIAL UNCHARACTERIZED Uncharacterized 13655-1365627317-27318 VCBS VCBS repeat domain 13657 27319 ZINC FINGER FYVE Zincfinger FYVE domain- 13658-13659 27320-27321 DOMAIN CONTAINING containingprotein PROTEIN ZINC FINGER- Zinc finger containing protein 13660-1366227322-27324 CONTAINING PROTEIN

Engineered Proteins.

The domains disclosed herein may be utilized in the creation of“engineered proteins.” As used herein, a “protein of the invention,” oran “engineered protein” will refer to a non-naturally occurring protein,wherein such protein comprises one or more domains selected from SEQ. IDNO: 1-13662. A non-naturally occurring protein means the protein is notfound in any wild-type species, having been engineered by molecularbiological techniques known in the art. For example, the engineeredprotein may comprise heterologous elements, i.e. elements from differentspecies. Alternatively, the engineered protein may comprise an anaerobicfungal protein lacking heterologous elements, but wherein the elementsof the protein have been modified in some way such that they differ fromthose of the native protein, for example by rearrangement, duplication,or deletion of elements.

The domains disclosed herein will impart various properties to theengineered proteins in which they are incorporated. In some cases, thedomain will comprise a structural element and will impart a structuralproperty to the engineered protein. In another embodiment, the domainwill comprise a binding domain and will impart a binding affinity forspecific binding partners. In other embodiments, the domain willcomprise a catalytic domain and will impart an enzymatic activity to theengineered protein.

The various domains of SEQ ID NO: 1-13662 encompass a wide variety ofdomains having diverse properties. One of skill in the art may readilyselect a domain of the invention for incorporation into an engineeredprotein based on the putative functions assigned to the domain. Theputative functions of various domains of SEQ ID NO: 1-13662 are listedas “domain descriptions” in Table 1. Methods of using the engineeredproteins of the invention will be readily ascertained by the skilledpractitioner based upon the properties of the one or more domains of SEQID NO: 1-13662 and any additional properties imparted by accessoryelements in the engineered proteins.

The proteins of the invention may include chemically synthesizedpolypeptides and recombinantly produced polypeptides comprising thedomain sequences disclosed herein. The scope of the invention will beunderstood to extend to derivatives of the disclosed domain sequences.The term “derivative,” as used herein with reference to the polypeptidesof the invention refers to various modifications, analogs, and productsbased on the polypeptide sequences disclosed herein, as described below.

Protein derivatives of the invention include substantial equivalents ofthe disclosed amino acid sequences, for example polypeptides having atleast 65%, at least 70%, at least 75%, at least 80%, at least 85%, atleast 90%, at least 95%, or at least 99% amino acid sequence identity toa disclosed domain and/or which retain the biological activity of theunmodified sequences.

Protein derivatives of the invention further include polypeptidesdisclosed herein which have been modified by such techniques asubiquitination, labeling (e.g., with radioactive or fluorescentmoieties), covalent polymer attachment, etc. Derivative proteins of theinvention include post-translational modifications of the polypeptideincluding, but not limited to, acetylation, carboxylation,glycosylation, phosphorylation, lipidation and acylation, etc.

Proteins derivatives of the invention further include polypeptidesdiffering from the sequences disclosed herein by amino acidsubstitutions. For example, amino acid substitutions that largelypreserve the secondary or tertiary structure of the original polypeptidemay be selected on the basis of similarity in polarity, charge,solubility, hydrophobicity, hydrophilicity, and/or the amphipathicproperties of specific residues. Determination of which amino acidsubstitutions may be made while maintaining enzymatic and otheractivities of interest is within ability of one of ordinary skill in theart of protein engineering. The invention also comprises substitutionswith non-naturally occurring amino acids, amino acid analogs, etc.

Proteins derivatives of the invention further include mutations in thedisclosed polynucleotide sequence intentionally introduced to enhance ormodify characteristics of the polypeptide, such as to alterpost-translational processing, binding affinities (e.g. introduction ofspecific epitopes for antibody binding), degradation/turnover rate,industrial processing compatibility (e.g. optimized expression,purification, etc.) or other properties.

The invention further comprises truncated versions of the proteindomains disclosed herein, for example C-terminal, N-terminal, orinternal deletions encompassing, for example, 1-20 amino acids. Theinvention further comprises isolated functional units from the discloseddomain sequences, for example isolated binding domains, catalyticdomains, and other motifs having useful structures or functions whichmay be used in isolation from the remainder of the protein.

The invention further comprises any of the disclosed polypeptidessequences which have been augmented with additional amino acids. Forexample, the invention also includes fusion proteins and chimericproteins in which a disclosed polypeptide sequences or sub-sequencesthereof is combined with other peptides, proteins, or amino acidsequences. Exemplary fusion or chimeric proteins include the discloseddomain polypeptide sequences, or sub-sequences thereof, which have beencombined with functional sequences from different proteins. Suchproteins may further include secondary polypeptide sequences that impartdesired properties such as enhanced secretion, or which enablepurification (e.g. His-Tags), immobilization, and other desirableproperties.

The invention further includes antibodies that specifically recognizeone or more epitopes present on the disclosed polypeptides, as well ashybridomas producing such antibodies.

Polynucleotide Constructs.

The scope of the invention further encompasses any nucleic acidconstruct which codes for an engineered protein of the invention orcodes for an engineered multiple enzyme complex of the invention. Forexample, the nucleic acid constructs of the invention may include anynon-naturally occurring nucleic acid construct which comprises one ormore nucleic sequences selected from SEQ ID NO: 13362-27324 or SEQ IDNO: 27328-27330, (corresponding to the proteins of SEQ ID NO: 1-13662and SEQ ID NO: 27325-27327). However, it will be understood that, due tothe redundancy of the genetic code and the diverging codon preferencesin different species, that nucleic acid sequences coding for theproteins of SEQ ID NO: 1-13662 and SEQ ID NO: 27325-27327 are notlimited to the fungal derived sequences disclosed in SEQ ID NO:13663-27324 and SEQ ID NO: 27328-27330, and may comprise any nucleicacid construct comprising a sequence coding for the selected domain.

The polynucleotide sequences of the invention encompass DNA, RNA,DNA-RNA hybrids, peptide nucleic acid (PNA) or any other DNA-like orRNA-like material. For clarity, the polynucleotide sequences disclosedherein do not encompass genomic DNA sequences as present in theirnatural source (e.g. native organism). The polynucleotide sequences ofthe invention do not contain introns or untranslated 3-prime and 5-primesequences. The polynucleotide sequences encompass translated sequencesonly.

The nucleic acid constructs of the invention encompass sequences whichare the reverse or direct complement of any of the disclosed nucleicacid sequences (or their derivatives, as described below).Polynucleotide constructs of the invention may comprise single-strandedor double-stranded polynucleotides and may represent the sense or theantisense strand. The nucleic acid constructs of the present inventionalso include nucleic acid sequences that hybridize to the disclosednucleotide sequences or their complements under stringent conditions.Polynucleotide constructs of the invention include sequences having highsequence similarity to the disclosed sequences (and their derivatives),for example, sequences having at least 80% homology, at least 85%homology, at least 90% homology, at least 95% homology, or at least 99%homology.

The polynucleotide constructs of the invention further encompassconstructs comprising sequences which are derivatives of the discloseddomain polynucleotide sequences. As used herein, with reference todomain polynucleotide sequences, the term “derivative” refers tocomplementary sequences, degenerate sequences, truncated or augmentedsequences, modified sequences, and other polynucleotides based upon thedisclosed sequences. One form of polynucleotide derivative contemplatedwithin the scope of the invention is a polynucleotide comprisingnucleotide substitutions. For example, utilizing the redundancy in thegenetic code, various substitutions may be made within a givenpolynucleotide sequence that result in a codon which codes for theidentical amino acid as coded for in the original sequence, and whichsuch change does not alter the composition of the polypeptide coded by apolynucleotide. Such “silent” substitutions may be selected by one ofskill in the art. Likewise, nucleotide substitutions are contemplatedwhich result in an amino acid substitution, wherein the amino acid is ofsimilar polarity, charge, size, aromaticity, etc., such that theresulting polypeptide is of identical or substantially similar structureand function as a polypeptide resulting from an unmodified sequence.Further, the invention also comprises nucleotide substitutions whichresult in amino acid substitutions which create a polypeptidederivative, as described above.

It is also understood by one of skill in the art that various nucleotideanalogs, modified nucleotides, and other compositions may be substitutedfor the nucleotides of the disclosed DNA sequences and theirderivatives, for example modified or non-naturally occurring nucleotidessuch as 5-propynyl pyrimidines (i.e., 5-propynyl-dTTP and5-propynyl-dTCP), 7-deaza purines (i.e., 7-deaza-dATP and 7-deaza-dGTP).Nucleotide analogs include base analogs and comprise modified forms ofdeoxyribonucleotides as well as ribonucleotides.

Additionally, substitutions in a disclosed polynucleotide sequence maybe made which enable the translation of polypeptides from thepolynucleotide sequence within a specific expression system. Forexample, as the polynucleotides of the invention are isolated fromfungal species, it is contemplated that the disclosed sequences may bemodified as necessary to enable or optimize expression of proteins ineukaryotic, yeast, insect, plant, mammalian, or in other expressionsystems such as cell-free and chemical systems. The selection of propersubstitutions for proper expression within a given expression system iswithin the skill of one in the art of molecular biology.

Polynucleotide derivatives of the invention also comprise augmented orchimeric sequences, wherein a disclosed polynucleotide sequence has beenmodified to include additional nucleotides. For example, a disclosedpolynucleotide sequence, or subsequences thereof, may be ligated withadditional polypeptide sequences which enhance expression (for example,promoter sequences), or which alter the properties of the resultingpolypeptide, such as sequences which enhance secretion, enable isolation(e.g. sequences which code for His-Tags or like moieties), enableimmobilization, or other useful sequences as known in the art.

The scope of the invention additionally includes vectors, comprising thepolynucleotide constructs of the invention integrated into vectors.Exemplary vectors include plasmids, phages, and viral constructs whichpromote efficient maintenance, amplification, and transcription of thepolynucleotide sequences in an expression system. The nucleic acidconstructs may comprise sequences integrated into the genome of anorganism by transduction techniques known in the art.

Engineered Organisms.

In one aspect, the scope of the invention encompasses organisms whichhave been genetically engineered to express one or more engineeredprotein of the invention, i.e. proteins comprising the protein domainsselected from SEQ. ID NO: 1-13662. The engineered organisms of theinvention further encompass organisms which express any of the ScaA fullproteins of SEQ ID NO: 27325-27327, or portions thereof. Likewise,engineered organisms may comprise the nucleic acid constructs of theinvention, for example, with the nucleic acid sequences beingtransiently expressed by the organism or being stably integrated intothe genome of the organism. In one implementation of the invention, theengineered organism is an organism expressing one or more of nucleicacid sequences selected from SEQ ID NO: 13663-27324 or SEQ ID NO:27328-27330.

Engineered organisms of the invention may comprise any species, forexample, fungal species, yeast, bacteria, plants, and other organismsgenetically modified to produce one or more engineered proteins of theinvention. The engineered organisms of the invention may furthercomprise cell lines, such as insect cell cultures, CHO cells, and othercell culture systems used in the production of recombinant proteins.

Engineered Enzymes for Bioprocessing.

The various inventions described herein may be applied in numerousbioprocessing methods. The present description is largely directed tobioprocessing methods for the digestion of lignocellulosic biomass intofermentable monomers. However, it will be understood that the engineeredproteins and organisms described herein may be applied in otherbioprocessing methods, for example, for the synthesis of chemicals fromfeedstocks, including polymers, biofuels, and others.

In one aspect, the engineered proteins of the invention encompassproteins which participate in the breakdown of lignocellulosic biomass.In one embodiment, the engineered proteins of the invention comprise aglycoside hydrolase or other enzyme capable of digesting a component oflignocellulosic materials. For example, the engineered enzyme of theinvention may comprise a cellulase, glycosidase, esterase, SGNHhydrolase, endoglucanase, cellobiohydrolase, Beta-D-glucan exohydrolase,beta-glucanase, phosphatidylinositol phosphodiesterase, pectin lyase,fucosidase, glycoside hydrolase, glycosyl hydrolase, hemicellulsase,xyanlase, galactosaminoglycan glycanohydrolase, amylase, chitinase,β-glucuronyl hydrolase, trehalase, glucoamylase, β-glucuronyl hydrolase,or acid phosphatase. In one embodiment, the engineered protein of theinvention is a glycoside hydrolase comprising one or more domainsselected from the group consisting of SEQ ID NO: 1-155; SEQ ID NO:1095-1309; and SEQ ID NO: 3851-3972; and SEQ ID NO: 9755-11844. In oneembodiment, the invention comprises an organism comprising apolynucleotide sequence which codes for a domain selected from thesequences of SEQ ID NO: 1-155; SEQ ID NO: 1095-1309; and SEQ ID NO:3851-3972; and SEQ ID NO: 9755-11844.

The scope of the invention encompasses methods of using engineeredproteins comprising lignocellulose degrading enzymes to facilitate thebreakdown of lignocellulosic biomass. In one such method, an engineeredprotein comprising a lignocellulose-degrading enzyme is produced in anengineered organism. Exemplary engineered organisms includeSaccharomyces cerevisiae, Zymomonas mobilis, Escherichia coli, andClostridium thermocellum. Systems which utilize such organisms inbiofuel production are known in the art. For example, the successfulheterologous expression of functional saccharization enzymes from afungal organism in yeast has been previously demonstrated, as describedin O'Malley et al., Evaluating expression and catalytic activity ofanaerobic fungal fibrolytic enzymes native topiromyces sp E2 inSaccharomyces cerevisiae. Environmental Progress and Sustainable Energy31:37-46, 2012.

In one such method, the engineered protein is produced by and issubsequently extracted from the organism. Purification or modificationsteps may be applied to the extracted enzyme. The enzyme may then beused in any applicable lignocellulosic bioprocessing system bycontacting it with an appropriate substrate under suitable conditionsfor enzymatic action to occur. In one embodiment, the extracted enzymeis used as a component of an enzymatic cocktail, for example, anenzymatic cocktail used in the saccharification of cellulosic materials.

In an alternative implementation, an engineered protein comprising alignocellulose degrading enzyme of the invention is expressed in anengineered organism, and the engineered organism is cultured with anappropriate lignocellulosic substrate to promote breakdown of thesubstrate.

Methods of using proteins comprising a lignocellulose degrading enzymeof the invention may be performed in any bioprocessing method, forexample, in ethanol production from biomass.

Multiple Enzyme Catabolic Complexes.

In another embodiment, the invention encompasses engineered enzymaticcomplexes. An engineered enzyme complex is a complex comprising multipleenzymes bound to a carrier or scaffold and further comprising one ormore substrate binding moieties. Such multiple enzyme complexes may beused to process a substrate with high efficiency due to the presence ofmultiple complementary enzymatic moieties being held in proximity to thesubstrate by the substrate binding moieties.

The engineered enzyme complexes of the invention are based on thebacterial cellulosome. In anaerobic microorganisms, cellulolytic enzymesare not secreted freely into the extracellular medium, as is generallythe case for aerobic microbes, but instead these enzymes assemble intolarge (MDa) multi-protein cellulolytic complexes called cellulosomes.Cellulosomes comprise various components. A first component is anon-catalytic protein that is anchored to the cell membrane of the hostcell expressing the cellulosome, typically a scaffoldin or itsequivalent. The scaffoldin comprises multiple domains called cohesins,which are sites to which functional moieties will attach. The functionalmoieties may comprise enzymes which comprise one or more dockerindomains. The dockerin domain will selectively bind complementarycohesion domains on the scaffoldin protein with high affinity. Thecelluolytic complex will typically further comprise one or morecarbohydrate binding moieties which bind lignocellulosic substrate. Thisbinding keeps the substrate in proximity to the catalytic enzymespresent on the cellulosome, facilitating degradation of the substrate. Aconceptual depiction of a cellulosome is depicted in FIG. 1.

In one aspect, the scope of the invention encompasses what will bereferred to as an engineered enzyme complex. The engineered enzymecomplex comprises: a scaffold protein; one or more catalytic proteins;and one or more substrate-binding proteins. In one embodiment, the oneor more catalytic proteins and one or more substrate-binding proteinsare bound to the scaffold protein by cohesion-dockerin interactions withcomplementary dockerin and cohesion elements being present on thescaffold and on the bound moieties. An engineered enzyme complex of theinvention is any enzyme complex wherein one or more component is anengineered protein of the invention. Alternatively, the engineeredenzyme complex of the invention is one comprising a scaffoldin proteinselected from SEQ ID NO: 27325-27327 (for example, being coded for bynucleic acid sequences SEQ ID NO: 27328-27330).

Tools and methodologies for the creation of multiple enzyme complexesand organisms expressing them are known in the art. Cellulosomes andlike enzyme complexes have been successfully produced wherein the typeand precise placement of enzymes is possible, for example as describedin Fujita et al., Synergistic saccharification, and direct fermentationto ethanol, of amorphous cellulose by use of an engineered yeast straincodisplaying three types of cellulolytic enzyme. Appl Environ Microbiol.2004 February; 70(2):1207-12. Additional methods of producing engineeredcellulosomes are described in United States Patent ApplicationPublication Number 20150167030, entitled “Recombinant cellulosomecomplex and uses thereof,” by Mazolli; United States Patent ApplicationPublication Number 20130189745, entitled “Artificial cellulosome and theuse of the same for enzymatic breakdown of resilient substrates,” bySchwarz; and U.S. Pat. No. 9,315,833, entitled “Yeast cells expressingan exogenous cellulosome and methods of using the same,” by McBride.

In one implementation of the invention, the engineered multiple enzymecomplex is an artificial cellulosome designed for the efficientdigestion of lignocellulosic biomass, wherein the one or more catalyticproteins comprise a plurality of proteins which degrade lignocellulosicmaterial, e.g. glycoside hydrolase proteins, and the one or moresubstrate-binding proteins comprise carbohydrate binding domains.

In one embodiment, the scaffold protein of the engineered enzyme complexis a scaffoldin protein comprising multiple cohesion domains. Forexample, the scaffoldin protein may comprise a scaffoldin proteinselected from the group consisting of SEQ ID NO: 27325-27327. In anotherembodiment, the artificial cellulosome comprises a dockerin domain. Inone embodiment, the dockerin domain comprises a dockerin domain selectedfrom the group consisting of: SEQ ID NO: 1420-3705 and SEQ ID NO:6590-8910. In another embodiment, the artificial cellulosome comprisesone or more carbohydrate binding domains. For example, the carbohydratebinding domain may comprise a carbohydrate binding domain selected fromthe sequences of: SEQ ID NO: 1061-1062; SEQ ID NO: 1325-1333; SEQ ID NO:1378-1419; SEQ ID NO: 3706-3850; SEQ ID NO: 3973-6254; and SEQ ID NO:9480-9605. In one embodiment, the artificial cellulosome of theinvention comprises one or more glycoside hydrolase proteins comprisingone or more domains selected from the sequences of SEQ ID NO: 1-155; SEQID NO: 1095-1309; and SEQ ID NO: 3851-3972; and SEQ ID NO: 9755-11844.

The scope of the invention further extends to nucleic acid sequenceswhich code for the various elements of the artificial cellulosomes. Thescope of the invention further encompasses engineered organisms whichexpress the various elements of the artificial cellulosome. The scope ofthe invention further encompasses methods of using such engineeredorganisms in the digestion of lignocellulosic biomass. It will beunderstood that the artificial cellulosomes of the invention comprise orare expressed in combination with anchoring moieties, secretory signalsand other elements required for the expression, secretion, and assemblyof cellulosomes, as known in the art.

The artificial cellulosomes of the invention enable components from twoor more species to be advantageously combined. Enzymes from non-fungalspecies can be utilized in anaerobic fungal cellulosomes, or enzymesfrom anaerobic fungi can be used in non-fungal cellulosomes. Forexample, in one implementation, the novel dockerin domains of theinvention derived from anaerobic fungi may be fused with enzymes orcarbohydrate-binding moieties from other species, such as from yeast oraerobic bacteria, and these combined elements can be bound toscaffoldins from anaerobic fungi. In another implementation, dockerinsfrom other species could be fused to catalytic proteins or carbohydratebinding domains from anaerobic fungi, facilitating the inclusion ofthese anaerobic fungal proteins in synthetic cellulosomes of otherspecies. This exchange of enzymatic elements from divergent species aidsin the creation of novel artificial cellulosomes having extendedenzymatic capabilities beyond those of wild type enzymatic complexes.Such hybrid systems can, with a single organism, recapitulate digestiveprocesses in the complex environment of the rumen, where fungal, yeast,and bacterial strains work in concert to digest complex biomass.

It will be understood that the engineered enzyme complexes of theinvention are not limited to multiple enzyme complexes which degradelignocellulosic material, and may be designed for efficient enzymaticaction of any kind on any substrate, as determined by the selection ofsuitable catalytic enzymes and substrate-binding moieties.

Polyketide Synthases

A very large number of important drugs and biologically active compoundsare from the group called polyketides. Polyketides are structurallydiverse compounds created by multi-domain enzymes or enzyme complexescalled polyketide synthases (PKSs). PKSs proteins are composed ofvarious peptide domains, each of which has a defined function. Variousclasses of PKSs are known, including Type I, Type II, and Type III PKSs.The Type I PKSs may be classified as either iterative or modular.

The iterative PKSs comprise a single module. The creation of apolyketide is initiated by binding a starting material to theacyl-transferase (AT) domain, the starting material typically beingAcetyl-CoA or malonyl-CoA. The bound starting material is then shuttledto the KS domain by an acyl carrier protein (ACP). An extender material,typically malonyl-CoA is then loaded into the complex by the AT domainand is added to the starter material by a condensation reactioncatalyzed by the ketosynthase (KS domain). Additional domains mayintroduce modifications to the bound chain by catalytic action.Additional extension reactions and modification reactions occur untilthe polyketide chain has reached its final length, which is specific foreach type of iterative PKS. The mechanisms by which final length iscontrolled are not known. When the polyketide has reached its finallength, a thioesterase (TE) domain releases the completed polyketide.Thus, such PKSs are called “iterative” because the final productpolyketide is produced in an iterative fashion by the repeated action ofthe domains to lengthen and modify the growing polyketide chain. Thevarious enzymatic domains of the iterative PKSs are not always used ineach cycle, allowing for more variability in final product composition.

In contrast, modular PKSs have multiple repeating modules, arranged fromthe N-terminal end of the PKS towards the C-terminal end. In eachmodule, the AT, ACP, and KS domains are repeated, and each module alsocontains its own combination of catalytic domains. Chain elongation isinitiated at the N-terminal end in the first module, and the growingchain is passed from module to module towards the C-terminal end,undergoing a single elongation and one or more enzymatic modificationsat each step. At the C-terminal module, a thioesterase (TE) domainreleases the completed polyketide.

Just as PKS domains can interact with one another, PKSs can interact, orform hybrid complexes, with non-ribosomal peptide synthases to formactive compounds (e.g. the anticancer compound epothilone).

Various classes of enzymatic PKS domain are known, including:

-   -   keto reductase (KR) domains, which reduces ketone groups to        hydroxyl groups;    -   dehydratase domains (DH), which reduces hydroxyl groups to enoyl        groups;    -   enoyl reductase (ER) domains, which reduce enoyl groups to alkyl        groups;    -   methyltransferase (MT) domains, which transfer methyl groups to        the growing polyketide;    -   sulfohydrase domains (SH); and    -   product template domains, which determine the folding pattern of        the polyketide backbone.        Additional non-PKS catalytic domains that work in tandem with        PKS domains include aminotransferases, pyridoxal-phosphate        transferases and HMG-CoA synthases.

The specificity of substrates and products for the domains varies, aswell as their order within PKSs. Accordingly, the different combinationsthe order of enzymatic domains within the PKS modules, and the differentarrangements of modules within modular PKSs means that these enzymes canbe configured to produce an immense range of final products.

The released polyketide may then be further modified by the action ofadditional enzymes, for example the addition of carbohydrate moieties ormethyl groups. The further complexity of PKS systems enables evengreater diversity of products, for example, two iterative PKSs caninteract to form a common product (for example as in the synthesis ofzearalenone). A PKS may also be fused with another enzyme to form asingle enzyme (for example as known in the synthesis of fusarin C).

Accordingly, PKSs, due to their modular nature, including multipledomains arranged within a module, and multiple modules within an enzyme,present a potential platform for the synthesis of myriad biologicalproducts.

Engineered PKS's.

Engineered PKS systems are known in the art and have been successfullyutilized to create various novel end products, some of which have neverbeen observed in nature. Various strategies exist for utilizing novelPKS enzymes, PKS modules, or PKS domains in the creation of diverse,potentially bioactive molecules. Exemplary PKS engineering techniquesare described in U.S. Pat. No. 9,334,514, entitled “Hybrid polyketidesynthases,” by Fortman et al.; U.S. Pat. No. 8,709,781, entitled “Systemand method for the heterologous expression of polyketide synthase geneclusters,” by Boddy et al.; and United States Patent ApplicationPublication Number 20130067619, entitled “Genes and proteins foraromatic polyketide synthesis,” by Page and Gagne.

The current state of PKS engineering allows for the recombination andswapping of various PKS enzymes, modules, and domains, enabling novelmeans of synthesizing compounds using engineered enzyme systems.Accordingly, there is a need in the art for PKS enzymes, modules, anddomains with novel functions, which such elements may be employed inengineered PKS systems. The novel PKS gene and protein sequences providethe art with novel tools for the creation of engineered PKS synthesissystems and enable the creation of novel compounds.

In one aspect, the scope of the invention encompasses engineeredproteins comprising engineered PKS enzymes. The engineered PKS enzyme ofthe invention may comprise a modular PKS or an iterative PKS. In oneembodiment, the engineered PKS enzyme of the invention comprises an acyltransferase domain. For example the engineered PKS may comprise an acyltransferase domain selected from the sequences of SEQ ID NO: 465-578;SEQ ID NO: 768-798; and SEQ ID NO: 12479-12509. In one embodiment, theengineered PKS comprises an acyl carrier protein domain. For example,the acyl carrier protein domain may comprise an acyl carrier domainselected from the sequences of SEQ ID NO: 604-767 and SEQ ID NO:12463-12473. In one embodiment, the engineered PKS comprises aketosynthase domain. For example, the ketosynthase domain may comprise aketosynthase domain selected from the sequences of SEQ ID NO:12546-12579. In one embodiment, the engineered PKS comprises athioesterase domain. For example, the thioesterase domain may comprise athioesterase domain selected from the sequences of SEQ ID NO:13417-13449. In one embodiment, the engineered PKS comprises aketoreductase domain. For example, the ketoredudctase domain maycomprise a ketoreductase domain selected from the sequences of SEQ IDNO: 12028-12043 and SEQ ID NO: 12526-12545. In one embodiment, theengineered PKS comprises a dehydratase domain. For example, thedehydratase domain may comprise a dehydratase domain selected from thesequences of SEQ ID NO: 12129-12152 and SEQ ID NO: 12771-12785. In oneembodiment, the engineered PKS comprises an enoyl reductase domain. Forexample, the enoly reductase domain may comprise an enoyle reductasedomain selected from the sequences of SEQ ID NO: 12510-12525 and SEQ IDNO: 13651-13654. In one embodiment, the engineered PKS of the inventioncomprises a product template domain. For example, the product templatedomain may comprise a product template domain selected from thesequences of SEQ ID NO: 12786-12787. The scope of the invention furtherencompasses engineered proteins which are not PKS enzymes, but whichcontain any of the aforementioned PKS domains.

The scope of the invention further includes engineered accessoryenzymes, which, as used herein, are engineered proteins with functionsaccessory to PKS enzymes. In one embodiment, the engineered proteincomprises an aminotransferase domain selected from SEQ. ID NO: 973-982.In one embodiment, the engineered protein comprises apyridoxal-phosphate transferase domain selected from SEQ. ID NO12862-12879. In one embodiment, the engineered protein comprises aHMG-CoA synthase domain selected from SEQ. ID NO 11883-11891.

The scope of the invention further encompasses nucleic acid constructswhich code for any of the aforementioned engineered PKS enzymes orengineered accessory enzymes. Furthermore, the scope of the inventionencompasses engineered organisms which express any of the aforementionedengineered PKS enzymes or which comprise a nucleic acid construct codingtherefor. Exemplary engineered PKS organisms include fungal species,bacterial species, yeast species, or plant species. The scope of theinvention further encompasses methods of creating complex molecules,including polyketides, utilizing the engineered PKS enzymes and/ororganism expressing such engineered PKS enzymes, wherein suitablesubstrates are exposed to such engineered PKS enzymes and/or organismexpressing such engineered PKS enzymes under conditions which facilitatethe synthesis of desired end-products.

Biofuel Production Using Novel Anaerobic Fungal Strains

Lignocellulosic material, or biomass, is a renewable and abundantmaterial and represents a potential feedstock for energy and chemicalproduction. However, the sugars contained in lignocellulosic materialsare locked in a complex of lignin, hemicellulose and cellulose and otherplant cell wall components. Currently, to extract fermentable sugarsfrom these recalcitrant feedstocks, lignin and hemicellulose must beseparated from the biomass prior to converting cellulose intomonosaccharides. As a result, bioprocessing of crude biomass entailsenergy-intensive pretreatment steps, and the addition of an expensiveand often inefficient cocktails of cellulolytic enzymes.

In contrast, anaerobic gut fungi that are resident in the gut ofherbivores routinely and efficiently degrade cellulose in complex,lignin-rich biomass. This is achieved through both mechanical andenzymatic processes: colonizing fungi develop a highly branchedrhizoidal network, or rhizomycelium, that penetrates and exposes thesubstrate to attack by secreted cellulases. Importantly, this uniqueinvasive strategy for plant cell wall degradation enables gut fungi tocolonize and decompose complex cellulosic feedstocks. Anaerobic gutfungi degrade plant particulates of dissimilar sizes at nearly the samerate, whereas the degradation rates of eubacterial populations steadilydecrease with increasing particle size. Therefore, anaerobic gut fungimay serve as a means to degrade diverse biomass feedstocks to usefulbioenergy compounds, without the need for expensive pretreatment,greatly reducing the cost and increasing the efficiency of biomassconversion to useful products.

Accordingly, there is a need in the art for novel organisms capable ofefficient conversion of biomass to usable fuel materials, and formethods of culturing such organisms. The four previously undescribedspecies of anaerobic fungal gut organisms described herein fulfill thisneed in the art, being capable of breaking down plant material toproduce ethanol, hydrogen, and other useful materials. Grown underanaerobic culture conditions, each of the four organisms is capable ofdegrading a wide range of lignocellulosic materials. For example, theorganisms can metabolize reed canary grass, glucose, fructose, avicel,and filter paper, demonstrating an ability to break down a wide range ofbiomass materials.

In addition to cellulosomes, which convert plant material intofermentable sugars, anaerobic fungi possess hydrogenosomes that convertthe released sugars to hydrogen gas following glycolysis. Hydrogenosomesare intracellular membrane-bound organelles that are analogous to themitochondria of aerobic microbes. In general, they metabolize malate andpyruvate to H₂, CO₂, formate, and acetate, generating energy in the formof ATP. The four novel organisms described herein are each capable ofhydrogen production from a range of feedstocks.

Accordingly, in one aspect, the invention comprises the use of Piromycesfinnis, Neocallimastix californiae, Anaeromyces robustus, and/orNeocallimastix sp S4 in the conversion of biomass feedstocks intoethanol, hydrogen, and other useful materials. The basic process of theinvention comprises introducing biomass feedstocks into a bioreactorvessel wherein culture conditions amenable to organism growth andmetabolism are maintained, allowing colonization and digestion ofbiomass by the organisms, and ongoing or subsequent harvesting ofend-products.

Anaerobic bioreactors and fungal bioreactors are known in the art. Forexample, exemplary fungal and/or anaerobic bioreactors are described in:Moreira et al., Fungal Bioreactors: Applications to White-Rot Fungi,Reviews in Environmental Science and Biotechnology, 2003, Volume 2,Issue 2-4, pp 247-259; Martin, An Optimization Study of a FungalBioreactor System for the Treatment of Kraft Mill Effluents and ItsApplication for the Treatment of TNT-containing Wastewater, inBioreactors, Auburn University Press, 2000; Palma et al., Use of afungal bioreactor as a pretreatment or post-treatment step forcontinuous decolorisation of dyes, 1999, WATER SCIENCE AND TECHNOLOGY;40, 8; 131-136; US Patent Publication Number US 20100159539 A1, Methodsand systems for producing biofuels and bioenergy products fromxenobiotic compounds, by Ascon; China Patent Publication 101374773,Method and bioreactor for producing synfuel from carbonaceous material,by Khor; and US Patent Publication Number 20100196994 A1, Fungicultivation on alcohol fermentation stillage for useful products andenergy savings, by van Leeuwen. Bioreactor designs amenable to thegrowth of the gut fungi described herein may be readily developedutilizing knowledge of the growth conditions optimal for anaerobic gutfungi growth and activity. The invention encompasses the use of any typeof bioreactor design, including batch reactors, flow-through reactors,and other bioreactor designs known in the art.

Anaerobic fungi are may be grown under substantially anaerobicconditions. Optimal temperatures for the growth and biomass digestiveactivity of such organisms is in the range of 25-40 C, preferably in therange of 30-40 C. Cultures may be grown without agitation, on soluble orinsoluble carbon sources, under a head space of 100% CO₂ gas. Liquidculture medium is preferred for growth and maintenance of the anaerobicfungi.

The culture media used to grow anaerobic fungi may be any known in theart, for example formulations based on those used for the cultivation ofrumen bacteria. For the most part, they are complex, non-defined media(pH 6.5-6.8) and contain up to 15% (v/v) clarified rumen fluid, butchemically defined media can be used as well, as described inMarvin-Sikkema, F. D., Lahpor, G. A., Kraak, M. N., Gottschal, J. C.,Prins, R. A., Characterization of an anaerobic fungus from llama faeces.J. Gen. Microbiol. 1992, 138, 2235-2241. Although phosphate buffers maybe used, a preferred buffer is bicarbonate with CO₂ in the head spacecontributing to the buffering system. Chemical reducing agents (e.g.,sodium sulfide and/or L-cysteine hydrochloride) are added to culturemedia pre- or post-autoclaving, after the majority of the O₂ has beenremoved from culture solutions by boiling and gassing with CO₂. Theseprocedures ensure that low oxygen levels of the culture medium aremaintained such that anaerobic fungal growth can be supported.

The methods of the invention encompass various steps. In a first step,biomass is fed into the bioreactor. Any form of cellulosic orlignocellulosic material may be utilized in the bioreactors and methodsof the invention. Biomass includes, but is not limited to, herbaceousmaterial, agricultural residues, forestry residues, municipal solidwastes, waste paper, and pulp and paper mill residues. Exemplaryfeedstocks include corn stover, canary reed grass, swtichgrass,Miscanthus, hemp, poplar, willow, sorgum, sugarcane, bamboo, eucalyptus.Additional feedstocks include byproducts of industrial processes, suchas pulping liquor (a byproduct of paper production).

Generally, it is preferred that the biomass feedstocks utilized in theprocesses of the invention be pre-processed to some degree prior todigestion by the fungal organisms. Preprocessing steps include grindingor other mechanical treatments which break the biomass into smallparticulates that may be more easily colonized and digested by thefungal organisms. Particulates in the range of 0.1 to 10 mm diameter,for example, may be used.

The biomass material is then inoculated with one or more fungal strainsselected from the group consisting of Piromyces finnis, Neocallimastixcaliforniae, Anaeromyces robustus, and Neocallimastix sp S4. Exemplaryinoculant material includes particulate material which has beencolonized by the fungal organism(s). As opposed to free zoospores, usingsuch material as the starting inoculum leads to more vigorous growth anda substantial reduction in culture lag. The inoculated biomass is thenallowed time to digest. The precise digestion time will vary dependingon (1) the composition and lability of the feedstock; (2) theparticulate size of the feedstock; (3) the concentration of inoculant;and (4) the specific bioreactor design. End-products of the digestionmay be removed from the bioreactor at set intervals, continuously, or atthe end of the digestion process. Removal of ethanol may be accomplishedusing methods known in the art for separation of ethanol fromfermentation broth. Likewise, evacuation of hydrogen gas produced by thedigestion may be accomplished utilizing means known in the art.

Working cultures of anaerobic fungi may require frequent sub-culturingin order to retain their viability. Most batch cultures remain viablefor 5 or 15 days in media containing soluble (glucose) or particulate(reed canary grass) substrates, respectively. Frequent sub-culturingintervals of 2-7 days with growth on particulate substrates aregenerally employed to ensure the continued production of viablecultures.

The processes of the invention may optionally further encompass theco-culture of the described anaerobic gut fungi with other organisms topromote optimal production of bioenergy materials. For example,co-culture of anaerobic gut fungi with highly effective anaerobicfermenting organism, yeast or bacterial strains can result in anoptimized system with efficient saccharization and fermentation.Similarly, production of specific end-products can be enabled byco-inoculation with organisms that convert the products of fungaldigestion to other materials. For example, production of hydrogenthrough fungal hydrogenosome activity allows other microbes to reduce H₂to the more energetically favorable methane gas. Co-culture withmethane-producing organisms such as Archaea shifts end-product formationtowards increased methane and acetate production, with a correspondingdecrease in lactate, succinate, hydrogen and ethanol accumulation. Inanother embodiment, co-culture of anaerobic gut fungi with methanogenscan be performed, which can significantly enhance the cellulosehydrolysis activity of the anaerobic fungi.

EXAMPLES Example 1. Sequence Identification

Fresh fecal material was collected from farm animals. Specimens wereisolated from 5×10-fold serial dilutions of fecal matter in anaerobicbuffer medium. Each dilution was then supplemented with 30 μg/mlchloramphenicol and grown in anaerobic medium containing milled reedcanary grass at 39° C. to enrich for gut fungi. Enrichment cultures thatwere positive for fungal, but not bacterial or protist, growth after5-10 days as determined by the generation of fermentation gases withoutan increase in culture turbidity were further subcultured. To generateunique fungal isolates, actively growing enrichment cultures werediluted up to 50-fold in serial dilutions with each dilution beingsubcultured for ˜4 days. This isolation procedure was repeated fivetimes until a uniform fungal morphology was observed from each specimenand a unique ITS sequence of the isolate was obtained. Subsequentphylogenetic analysis of this ITS sequence confirmed the presence of asingle novel fungal isolate in each culture. The new species were namedNeocallimastix californiae, isolated from goat feces, Anaeromycesrobustus, isolated from sheep feces, and Neocallimastix sp S4, isolatedfrom sheep feces, and Piromyces sp. finn, isolated from horse feces.

To identify novel sequences of interest, each strain was grown inanaerobic medium supplemented with either glucose or milled reed canarygrass at 39° C. After 2 days, the biomass was harvested and the totalRNA extracted using the Qiagen RNeasy kit. This RNA was then enrichedfor mRNA by selecting for polyadenylated RNA and made into a strandspecific cDNA library (single stranded). This cDNA library was thensequenced using an Illumina HiSeq next generation sequencing platform,using a standard workflow, and the resulting data was assembled into ade novo transcriptome using the TRINITY bioinformatics platform. Theassembled sequences were then annotated with the BLAST2GO package byBLAST sequence alignment against known protein sequences and proteindomain hidden Markov model (HMM) scans on Interpro of all possibletranslations of each transcript. The results were analyzed forstatistical significance and sequences of interest were noted.

Example 2. Identification and Characterization of Scaffoldin Proteins

Genomic analysis of 5 unique anaerobic fungi revealed the presence of1600 total dockerin domain proteins (DDPs) across genera with diversefunctionality, primarily related to plant carbohydrate binding andbiomass degradation. These include 15 glycoside hydrolase (GH) families,5 distinct carbohydrate-binding domains, and other functions implicatedin plant cell wall modification and deconstruction including pectinmodifying enzymes and expansins. 20.2% of DDPs belong to spore coatprotein CotH, which are also present in bacterial cellulosomes and arespeculated to also be involved in plant cell wall binding. Conversely,12.6% represent additional GH activities that are not present inbacterial cellulosomes (GH3, GH6, and GH45). The additionalβ-glucosidase conferred by GH3 in particular enables fungal cellulosomesto convert cellulose directly to fermentable monosaccharides, whereasClostridial cellulosomes produce low molecular weight oligosaccharides.

To find structural proteins that mediate assembly of DDPs, we isolatedthe supernatant and cellulosome fractions from three of these isolatesgrowing on reed canary grass as a sole carbon substrate. Size-exclusionchromatography (SEC) of the cellulosome fraction showed complexformation well within the MDa range, and SDS-PAGE revealed the presenceof many glycosylated proteins. Each fraction was subjected to tandemmass spectrometry and peptide sequences were mapped to their respectivegenomic and transcriptomic databases. Many of the proteins associatedwith these complexes were identified as GHs and other plant cell walldegrading enzymes. Proteins found in the cellulosome fraction wereparticularly enriched with NCDDs, indicating modular complex formation.Unexpectedly, all fractions also contained very large uncharacterizedproteins (hereafter named ScaA) with molecular weights (MW) ofapproximately 700 kDa. These ScaA proteins share 32% sequence identityover at least 92% sequence length (E value=0.0) between fungal genera.ScaA orthologs were also detected in the only other sequenced gut fungalgenomes, Piromyces sp. E2 and Orpinomyces sp. C1A, though the orthologdetected in O sp. CIA was incomplete likely due to fragmented genomeassembly.

Sequence analysis of these proteins across all 5 sequenced genomesshowed a predicted N-terminal signal sequence followed by a largeextracellular repeat-rich domain, and ending with C-terminal membraneanchor. Some of these proteins also encode predicted choline bindingrepeats (CBRs), which are known to bind glucan in prokaryoticglucosyltransferases. Thus, one possibility is that CBRs help mediatefungal cellulosome assembly, as many cellulosome proteins areglycosylated. Closer examination of the sequences revealed the presenceof a repeating amino acid sequence motif that is conserved among all ofthese homologues, and that occurs many times throughout these proteins.This motif is 20-30 amino acids long, typically includes with a Glyresidue immediately followed by two large hydrophobic residues (mostoften Tyr residues) and two non-consecutive downstream Cys residues.

Because these proteins are highly represented in secretome andcellulosome fractions from these diverse species of gut fungi, wehypothesized that they share a common role in these systems, possibly inDDP assembly. We hypothesized that these proteins function as scaffoldswhereby the repeating motifs act as dockerin-binding cohesins. Toinvestigate this, we recombinantly expressed fragments of the ScaAhomologues in Escherichia coli and performed enzyme linked immunosorbentassay (ELISA) using purified dockerin and anti-dockerin chemiluminescentsecondary antibody. These results showed a strong dockerin bindingsignal in wells containing the scaffoldin fragment cells compared tothose containing the empty vector control. As an additional control, aphenylalanine substitution to dockerin residue W28, previouslyidentified to be critical for binding, showed significantly reducedbinding activity. To determine the binding affinity of dockerin-ScaAinteraction, we purified Piromyces ScaA fragments and performedequilibrium analysis by surface plasmon resonance (SPR) against purifiedfungal dockerin. This analysis revealed that a single dockerin domaininteracts with the scaffoldin fragment with an approximate dissociationconstant (K_(d)) of 0.7 μM and a maximum response (R_(max)) of 80 RU.Additionally, the W28F dockerin mutant showed significantly reducedbinding affinity (K_(d), =2.0 μM, R_(max)=40 RU). Taken together, theseresults suggest that fungal scaffoldin proteins likely mediate assemblyof DDPs in fungal cellulosomes.

Though limited, previous studies have shown that fungal cellulosomes arequite divergent from their bacterial counterparts. For example, NCDDsoccur as tandem repeats at the N- and/or C-terminus, with the mostcommon form being a double tandem repeat (i.e. double dockerin) at theC-terminus. Though the functional role of this motif repetition is notknown, it has been previously noted that double dockerins bind to nativecellulosomes more efficiently than single domains⁵. Thus, wehypothesized that increasing the number of NCDD from one to two couldenhance binding affinity to the scaffoldin fragment. By ELISA, we foundthat the P. finnis single dockerin domain had higher binding affinitythan the double dockerin domain. However, by SPR, the double dockerinhad a comparable K_(d), but a higher R_(max) 120 RU, suggesting that thedouble dockerin is indeed capable of binding to more sites on the ScaAfragment than the single dockerin, which suggests that site specificitymay be more subtly encoded in the different dockerin domains and cohesinrepeats. Though the minimum sequence that defines a single cohesinremains to be determined, it is clear from our study that fragments ofthe scaffoldin encoding as few as four repeats are sufficient fordockerin assembly. Additionally, we cannot rule out that additionalbinding factors (e.g. glycosylation) found in native cellulosomes likelyfurther modulate the fungal dockerin-cohesin interaction, which arelacking in this recombinant system.

It has previously been reported that dockerins are capable of binding tocellulosome fractions from other species of gut fungi, which is a markeddeparture from bacterial cellulosomes. In agreement with thisobservation, a Piromyces dockerin is capable of binding to intactcellulosome fractions harvested from Anaeromyces and Neocallimastixspecies. Thus, we tested whether this cross-species binding activity isencoded specifically within ScaA homologues. To test this, we purifiedsingle dockerin domains from all three genera of gut fungi and testedtheir ability to bind to all combinations of ScaA fragments. Indeed, weobserved binding for all combinations tested and the binding signal waswithin standard error for almost all cases. Taken together, theseresults demonstrate that the fungal scaffoldin system is broadlyconserved across the anaerobic fungal phylum, allowing for highinterspecies infidelity. Therefore, it is not unreasonable to speculatethat in their native environments, for example the dense microbialcommunity of the herbivore rumen, fungal cellulosomes are a composite ofenzymes from several species of gut fungi. This is in stark contrast tobacterial cellulosomes, which have high species specificity. Thispromiscuity may confer a selective advantage of fungi over bacteria inthese environments.

In addition to the ScaA orthologs, other scaffoldin-like proteins werealso detected through proteomic analysis of cellulosome-associatedproteins. We tested three of these scaffoldins for dockerin bindingactivity and each tested positive over an empty vector control,suggesting that multiple scaffoldins likely exist in fungalcellulosomes. To search for scaffoldin-like proteins more broadly withinanaerobic fungi, we developed a Hidden Markov Model (HMM) based on therepeating motif from all 6 scaffoldins biochemically verified tointeract with dockerins. We found 95 unique loci in the genomes of A.robustus, P. finnis, and N. californiae, that bear a signal peptide andat least 10 cohesin repeats. Fewer loci (14) were detected in P. sp. E2and O. sp. CIA due to fragmented genome assemblies. Significantly, noloci were found in prokaryotes (˜2000 genomes) and only 1 or 2 weak hitsin other fungi (˜400 genomes), demonstrating this HMM is highly specificto fungal scaffoldins. These results indicate that gut fungi likelyproduce multiple scaffoldins for cellulosome assembly, and thesescaffoldins represent a new family of genes that is unique to the earlybranching anaerobic fungi.

While fungal scaffoldins and their NCDD ligands are specific to gutfungi, many plant biomass degrading enzymes that encode NCDDs are ofbacterial origin, which has been noted previously for a limited subsetof enzymes. Indeed, all five gut fungal genomes sequenced to date havelarge numbers of genes that are more similar to bacterial than toeukaryotic genes (9-13%). We aligned 1600 DDPs of the 5 anaerobic fungalgenomes with the 394 fungi currently deposited in JGI MycoCosm(excluding Neocallimastigomycota) and the 1774 bacteria and archaea inJGI Integrated Microbial Genomes (IMG). Of these proteins, 611 alignedbetter with bacterial than fungal proteins and 158 aligned exclusivelywith bacteria. Conversely, only 38 aligned exclusively with fungi, and372 aligned better to fungi than to bacteria. The remaining DDPs alignedequally with IMG and MycoCosm protein (3) or did not align with either(418). To determine whether this bacterial resemblance is the result ofinter-kingdom horizontal gene transfer (HGT), we queried the domainsthat are fused to NCDDs to extract homologous sequences from the samebacterial and fungal genomes. When possible, we built phylogenetic treesof the domain sequences. Out of 35 non-dockerin domains analyzed, 10(29%) passed our 2 criteria of 1) greater amino acid similarity tobacterial than to fungal sequences and 2) branching with bacterialrather than fungal sequences in its phylogenetic tree with >70%bootstrap support. The list of domains with an HGT signature includes 9CAZyme domains as well as the spore coat domain. However, this analysisdoes not inform us as to the direction of any possible HGT events.Subjecting NCDDs to the same analysis showed that there are no similarsequences in IMG at all, suggesting that many DDPs may be fusionsbetween native fungal and horizontally transferred bacterial components.Intriguingly, we found 12 fungal-bacterial homolog pairs where thebacterial protein is also a bacterial dockerin-domain protein. However,the sequence similarity between each pair of homologs encompasses onlythe catalytic domain and does not extend into the respective dockerindomains.

Over the past several decades, characterization of cellulosomes in fungihas been elusive, with multiple studies suggesting conflictingscaffolding schemes. Here, next-generation sequencing combined withfunctional proteomics uncovered a new family of genes that likely serveas scaffoldins in the cellulosomes of anaerobic fungi. The evidence forthis is 3-fold: (1) scaffoldins appear among the most representedproteins in supernatant and cellulosome fractions in three diverseisolates of gut fungi, and their amino acids sequences encode hallmarksof a membrane-anchored scaffoldin molecule, including an N-terminalsecretion motif, a C-terminal membrane anchor, and repeating amino acidmotif in between. These scaffoldins are encoded in all sequencedNeocallimastigomycota (representing 4 of the 8 genera of gut fungiidentified to date) and absent in other fungi. (2) Expression ofrepeat-containing scaffoldin fragments shows robust interaction withpurified dockerins by ELISA. (3) This dockerin-scaffoldin interaction isbiologically significant (K_(d)≈0.7 uM) as measured by SPR, whereas amutated dockerin derivative significantly reduced binding activity.Taken together, the identification of a new dockerin-binding proteinscaffold from fungi opens the way for exploitation of this modularinteraction for synthetic biology and substrate channeling. Finally, thepowerful degradation activity of gut fungi is provided by the diversefunctionality of its constituents, with 50 unique protein families ofbacterial and fungal origin, and the assembly of these constituents ontoscaffoldin molecules into cellulosome-like complexes. Perhaps the mostintriguing observation from this study is that fungal dockerins andtheir scaffoldin ligands have no sequence similarity to their bacterialcounterparts. Thus, it is possible that the cellulosome-based strategyfor plant cell wall degradation evolved in anaerobic gut fungiindependently of bacteria. This suggests that co-localizing plant cellwall degrading enzymes is so effective that nature has evolved it onmore than one occasion.

Example 3. Characterizing the Production of Secondary Metabolites inAnaerobic Fungi

In order to better understand the production of secondary metabolites bythe anaerobic fungi of the invention, bioinformatics tools andanalytical tools were employed. It was determined that numerous genesinvolved in the production of secondary metabolites were activelytranscribed in Piromyces finnis, Anaeromyces robustus, andNeocallimastix californiae. Genes involved in secondary metaboliteproduction included PKS genes as well as genes involved in the synthesisof nonribosomal peptides, terpenes, fatty acids, bacteriocins, andothers.

Additionally, LC-MS/MS analysis of fungal products was performed, and alarge number of peaks were observed, each corresponding to a compositionhaving unique mass and charge. These results provide promisingexperimental evidence that secondary metabolites are produced inabundance by these anaerobic fungi.

All patents, patent applications, and publications cited in thisspecification are herein incorporated by reference to the same extent asif each independent patent application, or publication was specificallyand individually indicated to be incorporated by reference. Thedisclosed embodiments are presented for purposes of illustration and notlimitation. While the invention has been described with reference to thedescribed embodiments thereof, it will be appreciated by those of skillin the art that modifications can be made to the structure and elementsof the invention without departing from the spirit and scope of theinvention as a whole.

What is claimed is:
 1. An engineered organism, wherein the organismexpresses the ScaA protein of Piromyces finnis comprising SEQ ID NO:27325.
 2. The engineered organism of claim 1, wherein the organism isselected from the group consisting of Saccharomyces cerevisiae,Zymomonas mobilis, Escherichia coli, Clostridium thermocellum, and ananaerobic fungal species.
 3. The engineered organism of claim 1, whereinthe organism expresses a synthetic cellulosome, comprising the ScaAprotein of Piromyces finnis comprising SEQ ID NO: 27325; one or morecatalytic enzymes capable of digesting lignocellulosic biomass; and oneor more carbohydrate-binding elements.
 4. An engineered organism,wherein the organism expresses the ScaA protein of Piromyces finniscomprising SEQ ID NO:
 27326. 5. The engineered organism of claim 4,wherein the organism is selected from the group consisting ofSaccharomyces cerevisiae, Zymomonas mobilis, Escherichia coli,Clostridium thermocellum, and an anaerobic fungal species.
 6. Theengineered organism of claim 4, wherein the organism expresses asynthetic cellulosome, comprising the ScaA protein of Piromyces finniscomprising SEQ ID NO: 27326; one or more catalytic enzymes capable ofdigesting lignocellulosic biomass; and one or more carbohydrate-bindingelements.
 7. An engineered organism, wherein the organism expresses theScaA protein of Piromyces finnis comprising SEQ ID NO:
 27327. 8. Theengineered organism of claim 7, wherein the organism is selected fromthe group consisting of Saccharomyces cerevisiae, Zymomonas mobilis,Escherichia coli, Clostridium thermocellum, and an anaerobic fungalspecies.
 9. The engineered organism of claim 7, wherein the organismexpresses a synthetic cellulosome, comprising the ScaA protein ofPiromyces finnis comprising SEQ ID NO: 27327; one or more catalyticenzymes capable of digesting lignocellulosic biomass; and one or morecarbohydrate-binding elements.